Linux MagazineFebruary 2021的目錄

If you’ve used Chrome OS, you know there’s a beauty in its simplicity. Over the years, there have been a few attempts at recreating that same simplicity for Linux, but many of those distributions have vanished. From the creator of Ubuntu Unity (https://ubuntuunity.org/), comes yet another attempt to create that user-friendly magic. The new distribution, called Ubuntu Web, is based on Ubuntu 20.04 and offers an open source take on Chrome OS. The developer, Rudy Saraswat, has employed the Gnome desktop (version 3.36, https://www.gnome.org/) to pull this off and includes plenty of preinstalled apps to make Ubuntu Web a distribution anyone can use. Included in the app listing you’ll find web apps for Mastodon, Twitter, SoundCloud, and a number of others from the /e/ Foundation. In order to really get…

Some programs, such as Netscape, Adobe Photoshop, and Microsoft Office, set the benchmark for future products. For file managers, the discontinued Norton Commander paved the way to easier copying, moving, and editing files at the MS-DOS command line. Norton Commander’s view, which was divided into two halves (hence the umbrella term “twin-pane file manager”) let users select files from a directory list in one pane by pressing Insert and then transfer them to the directory opened in the other pane by pressing F8. Norton Commander quickly spawned numerous clones, including Total Commander [1], Midnight Commander [2], Gnome Commander [3], PCManFM [4], and Krusader [5], as well as several other candidates. One of the classics, the graphical Sunflower [6] file manager, has been under continuous development for many years. With version…

Graphic images can give a website clarity and visual interest, but the web designer must contend with the tax that heavy graphic images place on bandwidth and load time. Photo images are typically scaled down to a lower resolution (and smaller file size) to run on the web, and for other types of image files, smaller is also almost always better. One way to reduce the size of web images is to rely on vector graphics whenever possible. The Scalable Vector Graphics (SVG) format was originally developed for use on the Internet. Although SVG typically leads to significant economies of scale when compared to pixel graphics, it has taken decades for web developers to become reasonably comfortable with it. The most popular tool for vector graphics on Linux is Inkscape.…

Popular desktop environments under Linux usually come with a gallery of background images to give the desktop an individual touch. But over time, seeing the same old images while the computer boots up can become boring. A few desktop environments, like KDE Plasma, have integrated a slideshow function to automatically rotate your desktop wallpaper at set intervals. However, most desktop interfaces under Linux do not offer this option. A simple solution to this problem is to install Variety [1], a tool that allows you to easily download and rotate different background images. Installation Many Linux distributions and some BSD derivatives come with the software already in their repositories. The project’s GitHub page [2] also provides the source code from which the application can be built. After downloading to your system,…

If there’s one trait that seems extraordinarily common to people in the Linux and open source communities, it’s the desire to deconstruct a process so it can be rebuilt better. You see this in software development, but it also reaches into many other geek-friendly niches, from retrocomputing and circuit design through to craft beer brewing and creating the perfect coffee. It could be because these subjects require a lot of data and a lot of parameter tweaking. In beer brewing, for example, even a simple brew requires a complex recipe, varying temperatures and pressures, and particular carbon dioxide levels. It’s also why software like BrewPi and Fermentrack, both of which we’ve previously looked at, produce such good results. They manage the data processing for us and allow us to track…

When CPUs were single core and either expensive or directly soldered onto the main board, many of us actually cared about what our CPUs were doing. This was because they couldn’t do much, and every cycle counted. The humble Commodore 64 CPU was running under a single megahertz in PAL-inflicted regions, for example, while the Amiga 500 only just broke the 7MHz barrier – while its rival, the Atari ST, gloated from the realm of 8Mhz. However, the Amiga did have an important advantage. You could swap out the scheduler for something more aggressive or more multitasking friendly, depending on whether you were accessing a BBS or number crunching a scene in LightWave 3D. Of course, now speed isn’t everything. Whether your CPU is clocked at 2, 3, 4, or…

To anyone from a desktop, phone, or tablet background, the humble command line can appear intimidating, best left to sci-fi nerds in fallacious hacking movies. But as many of us know, there’s no reason to be intimidated at all. The command line is often the best and simplest way to get certain tasks done, from editing documents to accessing remote servers. However, like KDE Plasma, its default configuration on many distributions can be a little austere, lacking modern shell features and a modern look. All of this can be solved by switching your terminal first to Zsh and then to its wonderful communitydriven Oh My Zsh framework. If you’ve not already switched, Z shell (Zsh) is best described as an extended version of Bash, the terminal most distributions use by…

The Linux community teems with “distro hoppers,” users who are always trying out new distributions. There is nothing at all wrong with that; we are always happy to discover new treasures in the Linux universe. Nevertheless, distro hopping can be hard work. Just downloading and transferring the ISO images to a USB memory stick takes time and involves risks. A simple typo in a command might cause you to move the image to the wrong place by mistake and accidentally delete important data. Wouldn’t it be far simpler if you could simply copy an ISO image off the web to a USB stick with a file manager and boot directly from the drive? Ideally, such a Linux USB memory stick would not only carry a distribution but even offer a…

In a previous issue of Linux Magazine [1], I outlined how to set up a Git Repository (Table 1). Once a repo is set up, you are ready to use Git [2] for version control. Version control in Git is about managing and creating branches (collections of files that are variations of each other). By making a branch, you can edit files without altering the original. Later, if you choose, you can merge branches to create a more advanced copy. The process of managing branches is so simple that branches tend to proliferate in projects that use Git, with branches being created for different users, subsystems or hardware architectures, each release, experiments, or any other criteria that may useful. In fact, while other version control systems also use branches, using…

For awhile, graphics cards have contained dedicated components for decoding and encoding video formats such as MPEG2, H.264, and H.265. In chip developer jargon, these embedded units are called application-specific integrated circuits (ASICs) [1]. CPUs without ASICs have a hard time decoding videos. However, graphics cards with their specialized circuits can decode video even on low-powered systems like the Raspberry Pi without jerking and with lower power consumption, thus shifting some of the load off the main processor. Lower power consumption means longer battery life and less heat generated, which in turn makes the system quieter. Interface On Linux, programs access the graphics chip’s acceleration functions via the Video Acceleration API (VA-API) [2]. The vainfo tool (included in the vainfo or libva-utils packages) shows you the algorithms supported by the…

Tiny Core Linux [1] offers an extremely lightweight Linux distribution whose default install gives you only the bare essentials. With no web browser, email client, or office suite, Tiny Core Linux gives you just enough to run a graphical session, making it ideal for older computers. While Tiny Core offers some software in its repository, if you intend to run a specialized application, such as a medical image viewer like the one used at my job, you will need to create your own package. In this article, I will show how to create your own packages, or extensions as they are called in Tiny Core Linux. Because the general methodology for packaging an application does not change much across distributions, this article also will give you a general overview of…

With a system like Linux, which is available to multiple users at the same time, it is important to keep an eye on the available resources. Is a graphical application running haywire and blocking all of the CPU’s cores? Is a user running a computationally intensive script and thus making work agonizingly slow for the server’s other users? Has a process gone wild and started to write increasing amounts of corrupted data to the hard disk? Such questions can be answered by various monitoring tools. The popular distributions typically preinstall Top. The program provides an overview of the active processes and measures both the CPU load and the RAM usage. Htop offers similar functions in a visually appealing format. Other programs display the network load (iftop) or determine which applications…

Back in the olden days of home computing, after your pocket money had run out and you’d completed your last computer game, the only thing left to do was revisit the games you’d long since finished. But this didn’t necessarily mean replaying them. With the help of a cartridge like the Action Replay on the Commodore Amiga, or a dismantled joystick button located between two serial port pins on a Commodore 64, you could reset your machine whilst keeping what was previously running in memory. You could then carefully peek and poke your way around the RAM – easily with the Action Replay – and even sideload a memory editor, allowing you to explore a disassembly of the original game code alongside the raw image, sound, and level data from…

It’s a brave project that challenges the status quo, and few commands are as much a part of the status quo as the humble ls. For most of us, ls and its permutations have long been committed to command-line muscle memory. You type ls to see what’s going on in the current directory, type ls -l to see file permissions and a little more detail, and type ls -l --time-style=full-iso to show off. And yet, this isn’t enough for the nat project, which boldly proclaims itself “the better ls” before you even get to the documentation. Nat is indeed an ls alternative, written in the system language du jour, Rust. Typing natls is intended to be a more fulfilling experience than typing ls. Your terminal bursts with color (if your…

There are quite a few decent open source online multiplayer first person shooter (FPS) games for Linux, such as Red Eclipse and Warsow. One particularly interesting example is an older game called Tremulous, which combines twitchy and instinctive combat with real-time strategy elements. Players are either humans or aliens, and they can either attack the opposition directly or choose to stay closer to home and build up the local base. This base building is much like you’d find in a real-time strategy game, fueled by the number of “frags” your whole team can score. As your team progresses, more options are unlocked, and theoretically your shooters have a stronger advantage. Tremulous hasn’t been updated for many years, but its unique gameplay, and even map compatibility, has been transplanted into another…

For a while, Linus Torvalds was concerned about the size of changes for the Linux 5.10 release. However, upon release of the rc6 candidate, that worry has subsided. To this point, Torvalds said, …at least this week isn’t unusually bigger than normal – it’s a pretty normal rc6 stat-wise. So unless we have some big surprising left-overs coming up, I think we’re in good shape.” Torvalds continued to say, “That vidtv driver shows up very clearly in the patch stats too, but other than that it all looks very normal: mostly driver updates (even ignoring the vidtv ones), with the usual smattering of small fixes elsewhere – architecture code, networking, some filesystem stuff.” As far as what’s to be expected in the kernel, there are two issues that have been…

ost of us experience Linux through the filter of a distribution. The exceptions are those who build their operating system from source files – there is even a project called Linux From Scratch to help that hardy minority. However, like most free software, distributions are hard to track. Many offer download statistics, but often one user does multiple downloads. The only data available is the statistics offered since 2001 by Ladislav Bodnar’s DistroWatch site [1]. It is not a precision instrument, since distributions can take some time to appear on the site for one reason or the other, but it is the best we have. Accordingly, every year or so, I like to scan the site to see what trends I can tease from its pages. I mainly see a…

Multimedia files, such as pictures, videos, or music tracks, often contain metadata (additional information not found in the file name or file attributes). Exchangeable Image File Format (EXIF), the standard for storing this metadata, provides details such as recording date, shutter speed, and aperture, among other things. Introduced in 2010, EXIF was originally used for digital camera photos. Today, EXIF has other applications and includes far more data than originally intended. For instance, applications such as Geeqie and digiKam use an image’s metadata to control the display order or to narrow a search. Usually, metadata is defined once and then not edited, because it contains important information about the multimedia data. In practice, there are exceptions where metadata access is both useful and necessary. For instance, many digital cameras still…

ow did the long command to connect to the database server work again? Shell power users know this memory problem and have taught themselves tricks over the years to repeat or resend modified versions of previously sent command lines. For example, the sequence!! repeats the last command (useful to prepend a sudo you might have forgotten); with Ctrl+R you can find and reuse commands that were sent further back in time by using search patterns. Bash remembers the entire typing history and shows it with the history command, which lists the tail end of what it has in memory (Figure 1). If you have ever taken a look at the .bash_history file in your home directory, you will know its little secret. This is where Bash simply appends every command…

While it sadly seems that Mozilla’s Firefox, and its Gecko web engine, are experiencing challenging market conditions, we’re still a long way from the dark days of many websites only working in Internet Explorer. This is mainly because the Blink web engine, used in Google Chrome, Microsoft Edge, and Opera, may have become dominant, and it is still open source, with a long open source origin story. Several projects, including favorites like Nyxt (formally Next) and qutebrowser, take advantage of this via QtWebEngine. While those big corporations undoubtedly wield a great deal of influence over Blink’s future, we’re equally free to fork it and change it however we wish. However, monoculture is seldom a good thing, especially when it comes to the World Wide Web, and that’s why other web…

It seems we can’t go a month without stumbling on another new or rebooted circuit-building tool. We recently looked at KTechLab, for instance, and several more in the months before that. This time it’s the turn of SimulIDE, a modest and relatively easy-to-use application that can help you build and test your own circuits. Despite being built with a modern Qt version, SimulIDE has a distinctly mid-‘80s Macintosh feel to its user interface. There are two reasons for this. The first is that the huge set of monochrome icons on the left shares a similar aesthetic with those early applications. The icons themselves represent the various components, generators, and annotations you can use in your own circuits, all of which are fortunately more modern than Aldus Page-Maker. The second reason…

There are many open source game engines. GamingOnLinux.com lists 21, from the amazingly comprehensive Godot to the humble Pygame. Bevy is a new addition, and if your ambitions are modest, it already offers a wonderful environment from which to build a cross-platform game. Unlike with Godot, though, Bevy development requires you to dive into the programming aspect from the beginning. This is because Bevy describes itself as a “data-driven” game engine using the Entity Component System (ECS) paradigm. This is the hot new thing in game development, and it is even being deeply explored by game engine behemoth Unity. Exploring Bevy’s excellent documentation reveals ECS to be a programming methodology based on composing your game from entities, components, and systems. As the documentation puts it, “Entities are unique things that…